Specialty bags are conventionally made from blanks cut from a single-ply or duplex (2-ply) sheet of stock material, such as paper, that is sealed along a longitudinal edge to form a tube and then sealed at one end of the tube to form a square-folded (SOS) bottom or a pinch bottom. In the 2-ply structure, the inner ply is typically a laminated plastic or foil film to provide barrier protection from a product which may contain oils or other ingredients which would affect the outer ply of the bag. Some bags may have a window which allows the product contained therein to be visible. The window is typically formed either by patching a window material on the inside of an aperture in a single-ply structure, or by cutting a window opening from the outer ply of a 2-ply structure and relying on the laminated inner film (such as polypropylene) to provide the see-through feature as well as the barrier protection.
In the fast foods and packaged products industries, promotional material is often distributed in conjunction with bags or cartons for a product. For example, flyers, gifts, coupons, and premiums are often dropped into a bag or inserted in a carton along with the product. Such insertions may become soiled by foods contained in the bag or carton, or may not be visible from the outside, thereby losing their promotional appeal. It is therefore desirable in these industries to have an improved bag or carton structure which allows promotional material to be fully visible and to remain clean and aesthetically pleasing to the consumer.